No description available.

This study aimed to address the current status of the United Arab Emirates date palms. The first chapter focused on the development of the date palm sector in the UAE. A huge increase in the date palm number was achieved in the past few decades. In the same time, there are critical issues facing this development, such as water demand, salinity, and Red Palm Weevil. The second chapter is a greenhouse experiment to test the growth of twelve date palm seeds at four NaCl levels, control, 3000, 6000, and 12000 ppm. Optimal growth found at control and 3000 ppm of NaCl. Relative growth rate (RGR), biomass, and NL decreased significantly by increasing salinity; however, no significant differences were observed in the average SGR for any cultivars. Increased NaCl leads to significant decreases in K+, Mg2+, and Ca2+ contents of plants. Na:K ratios were lower in shoots than in roots. Lulu, Fard, Khnaizi, Nabtat Safi, and Razez cultivars showed higher RGR and biomasses whereas Khnaizi, Mesally, and Safri had higher Na:K ratios than other cultivars in the control indicating higher Na+ discriminations from plant parts. The third chapter studied the vegetation change in the eastern region of the UAE. Due to shortage of fresh water resources, the vegetation of the eastern region of the UAE has experienced a series of declines resulting from salinization of groundwater. To assess these changes, field measurements combined with Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) based Soil Adjusted Vegetation Index (SAVI) were analyzed. Images from two dates, 1987 and 2000 were acquired to enable the computation of the greenness anomalies for three sites in the eastern region, Fujairah, Kalba, and Hatta. The results show an overall increase in the agricultural area, associated with a severe decrease in vegetation greenness and health conditions, particularly in the Kalba study area. The SAVI values decreased with increased soil salinity, permitting the identification of salt-affected areas. Potential areas of further research range from studying the effects of tree spacing and understory crops as immediate and potential solutions to maintain productivity and mitigate the salinity problem.

No description available.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Date palms (Phoenix dactylifera L.) and papayas (carica papaya L.) are two commercially important plantation crops. Their economic potential in South Africa and worldwide is increasing. However, due to disease, pests and socio-economic reasons, planting material is in short supply. Micropropagation provides a method for rapidly propagating selected superior cultivars for commercial and environmental interests. A satisfactory process for the regeneration of elite cultivars should result in individuals phenotypically and genetically identical to the explant from which they were derived. However, due to somaclonal variation generated during in vitro culture, the true-to-typeness is questionable. For this reason a southern African survey for off-types on date palms produced using somatic embryogenesis was conducted. Plant growth variations such as leaf variegation, seedless fruit, broad leaves, compact growth habit and parthenocarpic fruit were recorded and possible explanations for each phenomenon given. Factors influencing the date palm initiation process such as decontaminating agents, plant growth regulators, explant type and nurse cultures were investigated. A double decontamination process with 2.6% and 1.3% sodium hypochlorite was most effective at reducing contamination. Alternative plant growth regulators, TIBA and NAA were ineffective as a substitute to 2,4-D for somatic embryogenesis. The size of the explant and "nurse cultures" played an important role in explant growth and initiating callogenesis. A "nurse culture" reduced the time in culture significantly. The problem areas in the three commercial tissue culture techniques used for date palms were outlined. In the second part of the study, factors influencing initiation, multiplication and rooting of papaya were determined. Presoaking with antibiotic, Rifampicin, and various fungicides had a positive effect on decontaminating papaya explants, while Bronocide™ had little effect. Various methods and materials were used to optimize papaya multiplication and rooting in vitro. The growth and multiplication of papaya was optimal at 50 g l ¯¹ sucrose. Gelling agent, Gelrite, increased multiplication rates significantly but had a negative effect on overall growth causing plants to become vitrified. The addition of activated charcoal reduced vitrification but also reduced multiplication rate. Activated charcoal greatly improved overall growth of papaya and reduced leaf senescence. No vitrification was observed in multiplying papaya cultures where agar and Gelrite combinations were used, but multiplication rate was reduced compared to cultures grown on Gelrite alone. callus removal from the bases of papaya at subculturing reduced multiplication rate and influenced elongation, growth and leaf senescence. Lower concentrations magar and Gelrite improved rooting percentages, but did not provide good support. Damaged roots and lower rooting percentages were observed on plantlets treated with IBA for four weeks compared to those exposed for only two days. A one hour pulse with a higher concentration (5 mg l ¯¹) of IBA greatly improved rooting percentage and further eliminated a second subculture onto an IBA-free medium after two days. Good, strong roots with root hairs were produced on vermiculite medium containing equal volumes of DS salts and vitamins. Modified lids with cotton-wool plugs also reduced leaf abscission. In vitro grafting using stericrepe proved impractical, while grafting in vitro unrooted papaya plants onto ex vitro seedlings was more successful, using wedge and slant grafts. Grafts sealed with pegs and Parafilm™ were less effective. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Date palm (Phoenix dactylifera L.) is a fruit-bearing tree with numerous potential sustainable applications. Since ancient times, it has been considered a stable, secure, and sustainable food. This work provides comprehensive metabolic profiling of both parts, flesh and seed, of four P. dactylifera cultivars; Ajwa, Anbara, Sukkari, and Degelt Nour, which originated from two countries, Saudi Arabia, Tunisia. The analysis performed using mass spectrometry-untargeted metabolomics approaches, included a combination of LC-MS and GC-MS coupled to multivariate statistical analysis to reveal the differences in metabolite compositions among date varieties. The LC-MS seed results showed several classes of metabolites that belong to the flavonoids, phenolic acids, and amino acids derivatives, including citric acid, malic acid, lactic acid, hydroxyadipic acid, caffeic acid, which were at high concentrations in AJS followed by DNS and ARS. The LC-MS flesh analysis displayed that DNF had a high level of Isoquercitrin (flavonoid compound) and sinapic acid, and AJF was high concentrations level in hydroxyadipic acid and ascorbic acid. GC-MS concluded that seed samples of four date varieties are richer in metabolites classes than the flesh samples. The metabolites contributed to the seed metabolite compositions included several classes of amino acids, hydrocinnamic acids (caffeic, ferulic and sinapic acids), antioxidant phenolics, and long-chain fatty acids. The PCA and its loading analysis demonstrated the discriminating metabolites that were responsible for date varieties segregation, as HCA displayed the metabolic patterns and groups of metabolites that drive the clustering of the date samples, two groups of dates clustered together (AR and AJ) and (SR and DN). These clusterings are based on the similarities and differences observed in the metabolite compositions of the studied date samples that could be explained by differences in various metabolic responses and the environmental conditions, genotypes and geographical regions. This extensive date palm information would increase the potential of date fruits and seeds as low-cost sources of natural diet that may provide nutritious and bioactive components in the food and pharmaceutical fields to produce value-added products.